I've chosen the "AuthDirMaxServersPerAddr" option here for
simplicity, since it is used literally nowhere else besides the dirauth
module. Once we have all the infrastructure in place for this, we
can move more options into this structure.
All of these files contain "*.h", except for:
* src/app/config/.may_include
* src/test/.may_include
which also contain "*.inc".
This change prevents includes of "*.c" files, and other
unusually named files.
Part of 32609.